Tinners' snips are sized according to which aspect?

Tinners' snips are sized according to the overall length of the tool. This measurement is crucial because it determines the lever action and the cutting capacity of the snips. A longer pair of tinners' snips allows for greater leverage, which is beneficial when cutting through thicker materials or making longer cuts.

Understanding the sizing helps a user select the appropriate tool for a specific job, as the length can affect both the precision and the ease of use. The other aspects, such as the width of the blades or the size of the handle grip, may influence comfort and the type of cut but do not define the size of the tool itself. The thickness of the cutting edge can also vary, but it doesn’t reflect the overall measurement needed for categorizing the snips. Therefore, the overall length is the standard measure for sizing tinners' snips effectively.